How you prepare

Multimedia

If you're a candidate for epilepsy surgery, your pre-surgical evaluation may include:

Baseline electroencephalogram (EEG). In this test, electrodes are placed on the scalp to measure electrical activity produced by the brain.

Video EEG. A continuous EEG with video monitoring records your seizures as they occur. Because your seizure medications have to be reduced or temporarily stopped so that seizures will occur, you'll have to be admitted to the hospital for this test. Correlating the changes in your EEG with your body's movements during a seizure helps "pinpoint" the area of your brain in which your seizures are starting.

MRI or CT of the head. MRI and CT scans can identify structural problems — such as lesions or scar tissue in the brain — that could be causing seizures.

Single-photon emission computerized tomography (SPECT). The scan image varies in color depending on the amount of blood flow in different areas of the brain. Typically, blood flow is higher in the part of the brain where seizures originate. In some cases, doctors combine several types of imaging techniques to help locate the troublesome area of the brain.

Legal Conditions and Terms

Reprint Permissions

A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.